<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <input type="text" name="" id="t">
    <input type="text" name="" id="b">
    <script>
        var a=document.getElementById('t')
        var b=document.getElementById('b')
        a.value=null
        b.value=''
        // console.log(a.value,b.value)
        // console.log(a.value===b.value)
        // console.log(a.value==b.value)
        // console.log(typeof a.value,typeof b.value)
        // console.log(Boolean(null)==Boolean(''))
        // console.log(typeof null,typeof '')
        console.log(Number(['123w',123]))
    </script>
</body>
</html>